This invention relates generally to rotary driven tools, and in particular to downhole tools in horizontal directional drilling operations.
In horizontal directional drilling operations it is desirable to provide power to several and various downhole drilling components. Batteries, wire-line connections, and downhole fluid-driven generators have been employed to provide power to the downhole components. However, there remains a need for improvement.
The present invention is directed to a horizontal directional drilling machine. The machine comprises a rotary drive system and a drill string. The drill string is operatively connected to the rotary drive system to drive rotation of the drill string. The drill string comprises a plurality of dual-member pipe sections. Each section comprising a hollow outer member and an inner member positioned longitudinally therein. A downhole tool is supported within at least one of the dual-member pipe sections so that rotation of the inner member will drive operation of the downhole tool.
The present invention further comprises a pipe section assembly for use in a drill string comprising a plurality of dual-member pipe sections. Each dual-member pipe section comprises a hollow outer member and an inner member positioned longitudinally therein. The outer member is connectable with the outer members of adjacent pipe sections, and the inner member is connectable with the inner members of adjacent pipe sections. The interconnected inner members are rotatable independently of the interconnected outer members. The pipe section assembly comprises an elongate, hollow outer member interconnectable with the outer member of at least one of the dual-member pipe sections in the drill string; an elongate inner member arranged longitudinally within the outer member and is interconnectable with the inner member of at least one of the dual-member pipe sections in the drill string and rotatable independently of the outer member. The pipe section assembly comprises a downhole tool supported within the outer member and operatively connectable with the inner member so that rotation of the inner member drives operation of the downhole tool.
Still further, the present invention includes a method for generating power using a horizontal directional drilling machine including a rotary drive system attached to a drill string comprising a plurality of connectable pipe sections. Each pipe section has an inner member disposed longitudinally within a hollow outer member. Each outer member being connectable to another one of the outer members comprising the plurality of pipe sections and each inner member being connectable to another one of the inner members and rotatable independently of the outer members. The method comprises rotating the interconnected inner members, and converting rotation of the inner member of at least one of the plurality of pipe sections into electric or hydraulic power.
Finally, the present invention includes a power-generating apparatus comprising a hollow outer member; and an inner member positioned within the outer member, and rotatable independently of the outer member; and a power generator supported within the outer member and operatively connectable to the inner member for converting rotational energy from the inner member into electric or hydraulic power.